Ye H, Hao T L, Jin X R
Department of Pathophysiology, Tongji Medical University, Wuhan 430030.
Sheng Li Xue Bao. 2000 Oct;52(5):355-9.
The effects of erythropoietin (EPO)3 -enhancer on endothelium-dependent and endothelium-independent proliferation caused by hypoxia in cultured porcine pulmonary artery smooth muscle cells (PASMCs) were investigated with MTT test, H(3)-TdR incorporation and flow-cytometry. The results showed that (1) PASMCs exposed to hypoxia for 24 h proliferated significantly, which was suppressed by pretransfecting wild type EPO3 -enhancer fragments into PASMCs, but not by protransfecting mutant fragments; and (2) the conditioned medium of pulmonary artery endothelial cells (PAECs) exposed to hypoxia for 24 h promoted the proliferation of PASMCs. This effect was abolished when wild type EPO3 -enhancer fragments were transfected, but it persisted when mutant fragments were transfected. The results suggest that (1) the conditioned medium of hypoxic PAECs induces proliferation of PASMCs. This may be because that not only PAECs are sensitive to hypoxia, but also PASMCs respond to hypoxia directly; and the hypoxic responses of both endothelial cells (ECs) and smooth muscle cells (SMCs) can be inhibited by exogenous EPO3 -enhancer fragments. (2) Since there is a HIF-1 binding site in EPO3 -enhancer, there may be a common pathway for HIF-1 hypoxia signal transduction in hypoxic responses of ECs and SMCs.
采用MTT法、³H-TdR掺入法及流式细胞术，研究促红细胞生成素（EPO）3增强子对培养的猪肺动脉平滑肌细胞（PASMCs）中缺氧引起的内皮依赖性和非内皮依赖性增殖的影响。结果显示：（1）暴露于缺氧环境24小时的PASMCs显著增殖，将野生型EPO3增强子片段预转染至PASMCs可抑制其增殖，而预转染突变片段则无此作用；（2）暴露于缺氧环境24小时的肺动脉内皮细胞（PAECs）的条件培养基可促进PASMCs增殖。转染野生型EPO3增强子片段后此作用消失，而转染突变片段后该作用仍持续存在。结果表明：（1）缺氧PAECs的条件培养基可诱导PASMCs增殖。这可能是因为不仅PAECs对缺氧敏感，PASMCs也可直接对缺氧作出反应；外源性EPO3增强子片段可抑制内皮细胞（ECs）和平滑肌细胞（SMCs）的缺氧反应。（2）由于EPO3增强子中存在缺氧诱导因子-1（HIF-1）结合位点，ECs和SMCs的缺氧反应中可能存在HIF-1缺氧信号转导的共同途径。
